Advances in automated mining equipment now enable continuous coal mining devices to be operated by remote control, with a human operator located a safe distance from the mining face and from the mining machinery. One limitation on the ability to continue remote control mining deep into a mineral seam is the need to provide some means for removing the mined material as it is discharged from the miner. Various types of continuous haulage devices have been developed for this purpose, each with its own shortcomings. Representative examples of haulage systems are disclosed in U.S. Pat. Nos. 4,969,691; 4,474,287; 4,256,213; and 4,120,535. There continues to be a need, however, for a continuous haulage device which has the ability to automatically track a continuous miner as it proceeds into the seam, while maintaining the required recovery position beneath the miner discharge.
It is therefore the principle object of this invention to provide a system for intermediate continuous conveying of coal or other mined minerals from the discharge of a continuous mining device to a distant point where the mineral is stockpiled or transferred to another conveyor. The continuous haulage device of this invention is able to advance behind the continuous miner without interruptions for repositioning, and to follow the continuous miner without intervention, as it proceeds into the mine entry and beyond. Significantly, the subject haulage system is not mechanically coupled to the miner and does not rely on the miner for its locomotive power. The receiving end of the haulage system maintains its position beneath the miner discharge by means of a mechanical proximity sensor, which enables the system to mimic the irregular pattern of advancement typical of continuous mining systems.
In one exemplary embodiment, the haulage system of this invention is comprised of a continuous, flexible (preferably rubber) conveyor belt of sufficient length to extend from the mine entry to a mobile belt conveyor tailpiece assembly which follows the continuous miner. The system also includes insertable conveyor support roller cars which are added behind the mobile tailpiece as the conveyor is extended into the mine. A belt storage/feed device and tensioning device are located on the outby end of the conveyor and can be of any suitable conventional design.
The mobile tailpiece assembly serves as the receiving end of the conveyor, and may also include a feeder/breaker if desired. Its location must be maintained relative to the miner discharge end to enable the miner to operate continuously. The tailpiece assembly is mounted on electrically or hydraulically powered crawlers which are used primarily for alignment of the tailpiece with the miner as described below.
The support cars are of rigid construction with a cantilevered top roller assembly, allowing them to be inserted laterally into the moving conveyor belt. Each car is rigidly connected to the other by a "spine" structure along the centerline axis. Cars are supported by freely rotating tired wheels. Once connected, the cars are pulled into the drift by the advancing mobile tailpiece. The first car is connected to the trailing section of the mobile tailpiece by a wire rope or ropes passing through a sheave(s) mounted on the tailing section of the mobile tailpiece. The wire rope(s) return to the outby in a channel(s) provided on the conveyor roller support cars.
As the miner proceeds into a mine drift or seam, the mobile conveyor tailpiece follows, thus extending the conveyor belt. The insertable conveyor support roller cars are installed in the "free space" between the tailpiece (or the last car), and an outby support pulley (and associated winch). The cars are of rigid construction with a cantilevered top roller assembly, allowing them to be inserted laterally into the moving conveyor belt. Each car is rigidly connected to the other by a "spine" structure along the center line axis of each car. The cars are supported by freely rotating wheels (preferably with pneumatic tires) and, once connected, the cars are pulled into the mine drift by a unique cable arrangement described below. The first car is connected to the trailing section of the mobile tailpiece by one or more cables or wire ropes passing through sheaves mounted on the trailing section of the mobile tail piece. The wire rope or ropes return to the powered winch at the outby via a channel or channels provided on the conveyor roller support cars.
The mobile tailpiece crawlers do not have the tractive power to not only maintain the desired location behind the continuous miner, but also to provide the motive force for the belt roller support cars. Rather, the mobile tailpiece is only required to advance itself and to overcome the belt tension arising from the pulling of extended sections of the conveyor belt into the mine from the belt storage assembly. The mobile tailpiece is also equipped with two pairs of fixating hydraulic jacks, one pair at each of the forward and rearward ends of the tailpiece. Each jack is comprised of a double acting hydraulic cylinder which, when actuated, anchors the tailpiece between the roof and floor of the mine.
Upon advancing a predetermined distance beyond the anchored mobile tailpiece, a proximity sensor indicates the need for the mobile tailpiece and conveyor to follow. The fixating jacks on the mobile tailpiece are withdrawn, and the cable or cables relaxed to provide slack, thereby allowing the tailpiece to advance on its crawlers to align itself properly beneath the miner discharge, i.e., in overlying relationship. When the tailpiece is advanced the desired distance, the fixating jacks are actuated, again anchoring the tailpiece in place. Tension is then applied to the cable from the winch, thus advancing the conveyor support roller car train toward the tailpiece. When the single drift has been completed, the conveyor support roller cars are extracted by disconnecting the cable from the first car and pulling from the outby.
Thus, in one aspect, the present invention relates to a remote mining, continuous haulage system including a continuous miner, a mobile tailpiece assembly having a self-contained drive, said mobile tailpiece assembly adapted to receive mined material from the miner, and a plurality of conveyor support cars trailing the tailpiece assembly, the improvement comprising: means independent of the mobile tailpiece drive for pulling the plurality of conveyor support cars into the mine behind the mobile tailpiece.
In another aspect, the invention relates to a method of continuously operating a remote mining haulage system which comprises a continuous miner having a cutting head at a forward end and a discharge assembly at a rearward end; a mobile tailpiece carrying a forward end of an endless conveyor, the mobile tailpiece including means for anchoring the tailpiece within a mine, and further including at least one pulley mounted on a rearward end thereof; and a plurality of conveyor roller support cars extending behind the mobile tailpiece the method comprising the steps, in sequence, of:
a) advancing the miner into a mine drift while the mobile tailpiece is anchored in place within the mine;
b) upon the miner advancing a predetermined distance beyond the mobile tailpiece, releasing the mobile tailpiece;
c) advancing the mobile tailpiece to maintain the discharge end of the miner and the forward end of the continuous conveyor in alignment while the support cars remain stationary, and to introduce additional conveyor sections into the mine;
d) anchoring the mobile tailpiece;
e) advancing the plurality of conveyor support cars toward the mobile tailpiece by a flexible member controlled by a tension device outside the mine; and
f) adding additional conveyor support vehicles behind a last of the vehicles as required by extension of the conveyor belt.
The description of the invention above is based on its use with a drum type continuous miner in a drift mining installation. It will be understood, however, that the invention is not limited to this application, and may be installed with many continuous miner designs in various mining situations.
Other objects and advantages of the present invention will become apparent from the detailed description which follows.